The disclosure relates to a method and system of manufacturing a composite article. More particularly, the disclosure relates to removal of volatiles produced during composite laminate production.
Currently many methods of manufacturing a molded fiber reinforced, resin based, composite article, involves combining a liquid, or solid resin with a strong fibrous reinforcement. The combined materials can be cured and converted into a structural composite article by the application of thermal energy and pressure.
One such method of manufacturing the composite article is by use of vacuum bag processing. Laid up layers of fibrous material and resin are placed on an impervious mold and covered by an impermeable membrane sealed at its edges. The sealed assembly is heated to temperatures between about 135 degrees Celsius (275 F) to about 365 degrees Celsius (700 F). The combination of pressure and temperature provides the necessary conditions to promote resin flow and coalesce individual layers together and cure the resin. As the resin is cured, volatiles are produced.
A vacuum is applied inside the assembly during portions of the cure cycle to draw off the volatiles. A porous fabric is used proximate to the impermeable membrane and exterior to the article being cured to allow for a gaseous flow path for the volatiles to escape.
However, the volatiles such as water and alcohols in gaseous/vapor form and can get trapped inside the resin matrix or between layers of the composite article before being removed. The gases that get trapped form voids in the resin or between the layers. The voids formed in the composite article compromise the mechanical properties of the composite article. Delamination of the composite article may also result from the failure to remove the volatiles during production.
The compromised mechanical properties due to voids in the composite article results in large scrap rates during production. The large scrap rates are costly.
What is needed is an improved method for manufacturing composite articles whereby volatiles and other gases created during the process are removed.